The present invention relates to printed wiring board files, and more particularly to printed wiring board files employing printed wiring board guides mounted parallel to each other to support printed wiring boards in adjacent files.
Printed wiring board files mounting printed wiring boards are well known to those skilled in the art. One type employs four vertical supports located at the corners of a vertical column. Three mother boards are mounted to three supports in such a manner as to enclose three of the four vertical sides of the column. Horizontally oriented connectors are attached to the mother boards at fixed vertical intervals. The fourth side is retained free of obstruction to permit the insertion of printed wiring boards in the connectors. Printed wiring boards mounted in this manner form a vertical stack of horizontally oriented printed wiring boards.
Such files, while operating generally satisfactorily, require board spacing sufficient to accommodate modate the tallest component to be mounted on any printed wiring board. This results in inefficient use of space when only a small number of printed wiring boards mount such tall components. Also, due to the nature of the printed wiring board file, external means of removing heat generated by the printed wiring boards, e.g., a fan, is frequently found to be necessary.
Another type of file employs a metallic board cage mounting printed wiring boards vertically. The cage includes an upper surface, lower surface, two side surfaces, and a plurality of connectors mounted vertically across the back of the cage. Upper guides and lower guides are formed in the upper and lower surfaces, respectively. Each upper guide is formed by making two U-shaped cuts in the upper surface. Each cut has an elongated base and two short legs perpendicular to the base. The bases are parallel and opposite each other and the legs of each cut extend toward the legs of the other cut. Once cut, the portion of the surface internal to each U-shaped cut is then bent downward perpendicular to the upper surface along a line extending between the ends of each such cut to form the board guide. Guides are formed in the lower surface in a similar manner.
A primary disadvantatge of such a file is that costly guide cutting and metal forming equipment is required to manufacture the board cage and guides. Otherwise such files function well when used individually. However, when these printed wiring board files are stacked one above another in a rack or frame, the upper files, due to heated air from below mounted files, can overheat.
The present invention overcomes these heat and spacing problems by providing a new and improved arrangement for mounting printed wiring boards.